Industrial controllers are specialized computer systems used for the control of industrial processes or machinery, for example, in a factory environment. Generally, an industrial controller executes a stored control program that reads inputs from a variety of sensors associated with the controlled process and machine and, sensing the conditions of the process or machine and based on those inputs and a stored control program, calculates a set of outputs used to control actuators controlling the process or machine.
Industrial controllers differ from conventional computers in a number of ways. Physically, they are constructed to be substantially more robust against shock and damage and to better resist external contaminants and extreme environmental conditions than conventional computers. The processors and operating systems are optimized for real-time control and are programmed with languages designed to permit rapid development of control programs tailored to a constantly varying set of machine control or process control applications.
Generally, the controllers have a highly modular architecture, for example, that allows different numbers and types of input and output modules to be used to connect the controller to the process or machinery to be controlled. This modularity is facilitated through the use of special “control networks” suitable for highly reliable and available real-time communication. Such control networks (for example, ControlNet or EtherNet/IP) differ from standard communication networks (such as Ethernet) by guaranteeing maximum communication delays by pre-scheduling the communication capacity of the network, and/or providing redundant communication capabilities for high-availability.
As part of their enhanced modularity, industrial controllers may employ I/O modules or devices dedicated to a particular type of electrical signal and function, for example, detecting input AC or DC signals or controlling output AC or DC signals. Each of these I/O modules or devices may have a connector system allowing them to be installed in different combinations in a housing or rack along with other selected I/O modules or devices to match the demands of the particular application. Multiple or individual I/O modules or devices may be located at convenient control points near the controlled process or machine to communicate with a central industrial controller via the control network.
Before commissioning I/O modules in the system, it is typically necessary to determine the I/O requirements at various points of the controlled process or machine to properly match channels of the I/O modules to such requirements. For example, for analog sensors in a controlled process, such as level sensors for tanks, temperature sensors or position sensors, I/O modules having analog input channels should be used. However, for digitally controlled actuators in the controlled process, such as relays, indicator lights or small motors, I/O modules having digital output channels should be used.
As a result, resources are typically required for allocating and correctly matching channels of I/O modules to corresponding industrial control equipment. This requires time to implement, complexity to match, and limits flexibility of the system, particularly in the event that the controlled process or machine changes at a later date. Moreover, end users must typically purchase, maintain and store many different I/O modules to address each possible I/O type. If the required function of an I/O point changes due to a change in the, end users application, the I/O module often needs to be replaced causing inconvenience, additional cost and delay. It is therefore desirable to provide an I/O module for interfacing with industrial control equipment which eliminates one or more of the foregoing disadvantages.